1. Field of the Invention
The present invention generally relates to the field of data input devices. More particularly, the present invention relates to the field of keypad data input devices.
2. Related Art
A personal digital assistant (commonly referred to as a PDA) is a portable computer system. It is appreciated that the personal digital assistant is a portable handheld device that is used as an electronic organizer which has the capability to store a wide range of information that includes daily appointments, numerous telephone numbers of business and personal acquaintances, and various other information. Furthermore, the personal digital assistant has the ability to connect to a personal computer system, enabling the two devices to exchange updated information. Additionally, the personal digital assistant can be connected to a modem, enabling it to have electronic mail (e-mail) capabilities over the Internet along with other Internet capabilities over a wireless communication interface. Also, the personal digital assistant can be coupled to a networking environment.
Typically, the personal digital assistant includes a data input device such as a handwriting recognition device that can be utilized to control and operate the personal digital assistant. The handwriting recognition device receives user input handwriting stroke data, whereas a user utilizes a stylus to stroke alphanumeric characters and analog characters (e.g., *, &, @, $, etc.) on the handwriting recognition device. The handwriting recognition device processes the user input handwriting stroke data and transmits the processed data to another component (e.g., an electronic display device, a memory unit, a processor, etc.) of the personal digital assistant so that a particular operation or function can be performed. Personal digital assistants are enormously popular, in part because of their handwriting recognition device.
However, everyone does not use the handwriting device. Some potential users simply do not understand how the handwriting recognition device operates. Other potential users have experimented with the handwriting recognition device, but have been frustrated by not being able to get the handwriting recognition device to work right away, leaving them with the impression that the handwriting recognition device does not work for them. Moreover, some potential users believe that their own handwriting is too hard for a human to read, much less a handwriting recognition device. Other potential users feel that handwriting recognition is too error prone.
A software keyboard has been incorporated into the personal digital assistant. The software or virtual keyboard is displayed on the touch sensitive electronic display device of the personal digital assistant when invoked by the user. Refer to prior art FIG. 1 for an example of a software keyboard on a personal digital assistant. The user utilizes a stylus to select a particular keyboard character. Unfortunately, when the software keyboard 131 is displayed, the user experiences a marked reduction in the amount of space, on the touch sensitive electronic display device 130, available to display data.
The company SOFTAVA has developed the product Silkyboard as a solution for the perceived problems with the handwriting recognition device. The Silkyboard includes a keyboard template that is positioned over the handwriting recognition device. Thus, a user can tap on the appropriate location on the keyboard template to select and input a particular keyboard character. Moreover, the user can stroke characters on the keyboard template, causing the handwriting recognition device to detect and to recognize the stroked characters as particular alphanumeric characters or particular analog characters. Refer to prior art FIG. 2 for an example of a keyboard template 140 positioned on the touch sensitive display device 131. However, the Silkyboard has several disadvantages. First, the user finds it cumbersome, distracting, error-prone, difficult, and unintuitive to stroke characters over the keyboard template. Secondly, the user becomes dependent on the keyboard template rather than learning and employing the productivity enhancements of the handwriting recognition device, preventing the user from fully experiencing the power of the handwriting recognition device.
In addition, the company FTLab has developed the product Thumb Type as a solution for the perceived problems with the handwriting recognition device. Now referring to FIG. 3, the Thumb Type includes a special sheet having keyboard keys molded from high precision plastic and arranged with an approximate 6-millimeter (mm) pitch on the special sheet. This special sheet is positioned over the handwriting recognition device. The Thumb Type is designed so that the user holds the personal digital assistant in both hands and types using both thumbs. If the user desires to employ the handwriting recognition features of the handwriting recognition device, the Thumb Type enables the user to display the handwriting recognition feature on the touch sensitive electronic display device of the personal digital assistant. Thus, the user can stroke characters on the touch sensitive electronic display device rather than on the handwriting device, causing the handwriting recognition device to detect and to recognize via the touch sensitive electronic display device. Besides the disadvantages discussed in connection with the Silkyboard, the Thumb Type also has the disadvantage that the handwriting recognition feature displayed on the touch sensitive electronic display device further reduces the productivity space available for the user on the touch sensitive electronic display device and interferes with normal viewing of the data displayed on the touch sensitive electronic display device. Refer to prior art FIG. 3 and FIG. 4 for examples of thumb activated keyboards 120 coupled to a personal digital assistant 100.
Despite the advancements of thumb activated typing devices for personal digital assistants, there still exist many problems using keyboards with portable electronic devices. One prevalent concern of personal digital assistant users that utilize thumb activated input devices is accuracy. Many of the thumb activated input devices are very small and the keys of the device are very close together to keep the device as compact as possible. The result of the compact design is a tendency for users to unintentionally select the wrong key or multiple keys when using the device because these small keypads do not offer much tactile feedback as to key navigation. In addition, multiple keys are pressed because of the relatively small size of the keys with respect to the size of the fingers and thumbs. This leads to inaccuracy and ultimately loss of efficiency. Often the user presses multiple keys at once.
Thus, there exists a need for a miniature keyboard that allows the user to accurately and confidently input the desired characters while maintaining a small and compact design that is desired by users and useful for portable applications.